It is known to submit fabrics, for a better finish thereof, to a so-called decatizing operation wherein the fabric, coupled with a support element, called "back cloth", is subjected to steam action in association with a determined mechanical behaviour. There are various types of decatizing, above all according to the mechanical action exerted, e.g. of either compression or drawing, or depending on the fact that decatizing is made freely or in autoclave.
It is also known that the best results of decatizing are obtained in an autoclave at the inside of which the fabric piece is fed in subsequent batches, being wound on a perforated cylinder. The decatizing operation in the autoclave has been tentatively made continuous, and affords remarkable advatanges by eliminating the need of opening the autoclave, taking off the treated fabric roll therefrom and introducing the subsequent roll with consequent dead times and reduction of productivity, as well as the generation of transient periods at each cycle before reaching the value of normal working pressure within the autoclave.
With the Italian Patent No. 1.202.577 in the name of the same applicant has been proposed an autoclave continuously decatizing apparatus which solved most of the difficulties that in the past had prevented adequate development of this technology. However there still remained certain unsolved problems relating mainly to the steam tightness in the zone where the fabric with the back cloth is fed and the so-called "sandwich" gets off from the autoclave. As a matter of fact in the continuos autoclave decatizing a zone of communication with the outside cannot be avoided which, even if reduced to a slot only, provides for leakage of the pressurized steam.
Therefore it is an object of the present invention to provide a device for feeding a fabric into an autoclave and for the withdrawal therefrom such as to show an efficient seal action against steam under pressure in spite of having a particularly simple structure.